Leprosy is an ancient disease caused by the acid-fast bacillus Mycobacterium leprae, also known as Hansen's bacillus. M. leprae is an obligate intracellular microorganism with a marked Schwann cell tropism and is the only human pathogen capable of invading the superficial peripheral nerves. The transmission mechanism of M. leprae is not fully understood; however, the nasal mucosa is accepted as main route of M. leprae entry to the human host. The complete sequencing and the comparative genome analysis show that M. leprae underwent a genome reductive evolution process, as result of lifestyle change and adaptation to different environments; some of lost genes are homologous to those of host cells. Thus, M. leprae reduced its genome size to 3.3 Mbp, contributing to obtain the lowest GC content (approximately 58%) among mycobacteria. The M. leprae genome contains 1614 open reading frames coding for functional proteins, and 1310 pseudogenes corresponding to 41% of the genome, approximately. Comparative analyses to different microorganisms showed that M. leprae possesses the highest content of pseudogenes among pathogenic and non-pathogenic bacteria and archaea. The pathogen adaptation into host cells, as the Schwann cells, brought about the reduction of the genome and induced multiple gene inactivation. The present review highlights the characteristics of genome's reductive evolution that M. leprae experiences in the genetic aspects compared with other pathogens. The possible mechanisms of pseudogenes formation are discussed.
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http://dx.doi.org/10.1016/j.actatropica.2019.105041 | DOI Listing |
J Clin Tuberc Other Mycobact Dis
February 2025
Department of Dermatology, Venereology and Leprosy, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, Maharashtra, India.
Lepra reactions are acute episodic inflammatory reactions that occur during illness due to abrupt changes in the body's immunological response against Mycobacterium leprae. These are of two types, type 1 and type 2. Type 2 reaction is also called Erythema Nodosum Leprosum (ENL).
View Article and Find Full Text PDFTrop Med Int Health
January 2025
Programa de Pós-graduação em Ciências da Saúde: Infectologia e Medicina Tropical, Faculdade de Medicina, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brazil.
Objectives: The purpose of this study was to determine reference points for thermal perception in cutaneous lesions of leprosy, a disease caused by Mycobacterium leprae characterised by hypoesthesia in skin lesions due to nerve and Schwann cell infection. Early diagnosis is essential to control transmission and effectively treat the disease.
Methods: Quantitative thermal testing (QTT) has been proposed as a valuable tool for early detection of the disease, initiation of treatment, and monitoring of nerve damage.
Mod Rheumatol Case Rep
January 2025
Hospital Universitário Professor Edgard Santos, UFBA, Salvador - BA, Brazil.
Jaccoud's arthropathy is a deforming, non-erosive form of arthritis initially described in patients with rheumatic fever. However, it has been recently observed more frequently in those with systemic lupus erythematosus. Cases of Jaccoud's arthropathy have also been described to be associated with other conditions.
View Article and Find Full Text PDFJ Clin Tuberc Other Mycobact Dis
December 2024
Department of Microbiology and Virology, School of Medicine, Jiroft University of Medical Sciences, Jiroft, Iran.
Background: Leprosy is a chronic infectious disease caused by () However, the emergence of drug-resistant strains of this bacterium, especially multidrug-resistant (MDR) strains, is a serious concern. This study aimed to evaluate the global prevalence of MDR and its implications.
Methods: Using PRISMA guidelines, we systematically reviewed ISI Web of Science, MEDLINE, and EMBASE up to August 2023 to assess the prevalence of MDR .
Bullous type 2 lepra reactions are a rare initial presentation in leprosy that can complicate the disease with vesiculo-bullous lesions. Early recognition and differentiation from other bullous disorders are critical for timely corticosteroid and multidrug therapy initiation to improve patient outcomes.
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